Study On Shield Channel Segment Concrete Durability Of Resistance To Chloride Ion And Service Life Prediction

At present, China is in the golden age of infrastructure. A large numberof subway tunnels, high speed railways and roads, subsea tunnels are being constructured. Especially for undersea tunnels, occurrence of complex geotechnical conditions, sensitive surroundings, long-term effects in the external environment, structure and properties will deteriorate. If damage occurs, it can not be replaced. Therefore, the durability of Underwater Shield Tunnel concrete segment structure, will be an important research direction in the future of concrete structures.This paper focuses on the Shantou city project-"Josue Channel durability and impermeability thematic studies tunnel structure" as the basis, use method of literature research, theoretical analysis and experimental research, in the chloride ion erosion environment, research Shield Tunnel concrete anti chloride corrosion durability and life prediction. The main contents include:(1) Based on the analysis of a variety of factors affect the chloride ion diffusion, Combined with the actual engineering channel, establish a comprehensive model of concrete to chloride ion diffusion to determine the main parameters.(2) Conduct experimental study of chloride ion diffusion properties of concrete in the marine environment. Inspect the water-cement ratio, fly ash aggregate performance impact of chloride diffusion properties and concrete chloride ions Binding capacity. And in the light of the experimental data, draw curves that chloride ion with the depth of diffusion. Obtain the values of chloride ion diffusion coefficient and chloride ion concentration and the critical chloride concentration by fitting under different conditions, and discuss these parameters with the variation of affection of the external conditions.(3) Analyzes the forces of Josue tunnel segments concrete structures. Through literature research, combined with the existing theory, then analyze the influence that chloride stress of tube sheet structure on corrosion rate. Get the changes in the relationship between the two obtained to provide the theoretical help for the life prediction of Josue Channel segment concrete.(4) On the basis of the above experimental study and numerical simulation, comprehensive Analyzes chloride ion diffusion model probabilistic characteristics of each factor, based on Reliability Theory, use the previously established a comprehensive model of chloride ion diffusion, predict Shantou Josue channel shield segment life of concrete structures, in chloride environment.